Space resonant system



Feb. 25, 1947. Q QT U 2,416,567

- SPACE RESONANT SYSTEM Filed Oct. 25, 1942 fig.

ANOEflggR/D \LOLTAGE RE D IN HASE CURRENT VOLTAGE I A d w' ANODE-GRID aVOLTAGE POSITION 0F COUPLING SLOT Inventor; Elmer D. Mo Arthuw;

His Attorney.

Patented Feb. 25, 1947 SPACE RESONANT SYSTEM Elmer D. McArthur,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application October 23, 1942, Serial No. 463,087

My invention relates to space resonant systems and more particularly toultra high frequency systems for the utilization and production of ultrahigh frequency energy.

- It is an object of my invention to provide a new and improved ultrahigh frequeny space resonant system.

It is another object of my invention to provide a new and improved ultrahigh frequency space resonant system comprising improved coupling meansfor interconnecting a plurality of space resonant regions.

It is a further object of my invention to provide a new and improvedspace resonant system comprising coupling means for interconnecting aplurality of space resonant regions and which is suitable forutilization in a system intended to operate over a wide range offrequency without entailing adjustment of the coupling means.

Briefly stated, in the illustrated embodiment of my invention I providea new and improved ultra high frequency space resonant system whichconstitutes, as an energizing or control element of the system, anelectric discharge device includa plurality of enclosed electrodesincluding an anode, a cathode and a grid andin which anode-grid andgrid-cathode space resonant regions are defined by a, plurality ofconductive members which may be concentric. The intermediate memberforming the common boundary between the two regions, or the memberconnected to the grid of the discharge device is provided with anopening positioned within the vicinity of the maximum of the anode-gridstanding potential wave, thereby constituting a coupling orcommunicating path between the respective regions. This opening may havea configuration such that it has an appreciable axial or longitudinaldimension to permit adjustment of th operating frequency of the spaceresonant system as a whole, whereby the desired degree of coupling isobtained throughout the range of operating frequencies withoutnecessitating adjustment of the coupling means. For example,

the opening may have a helical configuration and is of such width thatits presence will not materially disturb the desired wave transmittingand propagating characteristics of the respective regions, and at thesame time affords the desired coupling.

For a better understanding of my invention, reference may be had to thefollowing description taken in connection with the accompanying drawing,and its scope will be pointed out in the appended claims. Fig. 1diagrammatically illus- Claims. (01. 2504s) 2 trates an embodiment of myinvention as applied to a space resonant system including an electricdischarge device and three concentric conductive or metallic cylindersconnected to the electrodes of the discharge device, and wherein thecoupling means constitutes a helical opening, or a pair of suchopenings, in the cylinder constituting the common boundary between theanode-grid and the grid-cathode regions. Fig. 2 is a detailed view ofthe discharge device employed in the arrangement of Fig. 1. Fig. 3represents certain features of the space resonant system and thecoupling opening or slot.

Referring to Fig. 1 of the accompanying drawing, my invention is thereillustrated as applied to an ultra high frequency space resonant systemwhich may include, as a control element thereof, an electric dischargedevice I which is associated with apluraiity of metallic or conductivemembars which define a plurality of space resonant regions. Prior to thedescription of the space resonant system as an entirety, it is believedthat reference may initially be had to Fig. 2 wherein the dischargedevice I is shown in more detail. The discharge device I includes aplurality of enclosed electrodes, such as a metallic cylindrical anode2, a cylindrical cathode 3 having its emissive surface 4 facing the endof anode 2, and a grid 5 spaced between the anode 2 and cathode 3 andpreferabiy lying in a plane spaced a small distance from the cathodeemissive surface. The discharge device I is constructed preferably tohave a generally stepwise configuration and constitutes a plurality ofmetallic members or discs r 5, l and 8 which support anode 2, grid 5 andcathode 3, respectively. It will be observed that the diameters of discs68 progressively increase to afford the above mentioned stepwiseconfiguration. Disc 8 may be formed integral with a cylindrical skirt 9which serves as a supporting or securing means between the elements ofthe discharge device and base ill. Discs 6, 1 and 8 are maintained inspaced relation with respect to each otherby means of a pair ofcylindrical insulating cylinders H and I2 which are sealed to the discsand constitute in part an enclosure for the electrodes of the dischargedevice.

Cathode 3 is provided with a. flanged part l3 which parallels theunder-surface of disc 8 and is spaced therefrom by means of aninsulating member or washer M. In this manner, the oathode 3 iselectrostatically coupled to disc 8 but electrically insulated therefromso far as direct currents are concerned. Unidirectional current orpotential may be applied to cathode 3 bymeans of conductors I and I6which are terminated in contact pins I1 and I8 secured to base ill.Cathode heating element or coil I9 is provided with a pair of conductors2i! and 2| which are likewise terminated in contact pins 22 and 23 alsosecured to base I9. It will be appreciated, of course, that conductorsI5, I6, and ill are sealed to a metallicheader (not shown) locatedWithin the base Ill, this header also being, of course, welded orsoldered to the skirt 9 thereby completing the evacuated enclosur forthe electrodes of the discharge device.

In order to afford a high frequency connection mean for the dischargedevice, anode 2 may be provided with an enlarged section or part 24. Itwill be appreciated that the anode 2 and disc 6 are closely fitted inorder to maintain the desired low pressure within the discharge device.The discharge device described above is the prior invention of James E.Beggs and is described and claimed in his copending application, SerialNo. 436,633, filed March 28, 1942, and assigned to the assignee of thisinvention.

Referring again to Fig. 1, I employ means in conjunction with thedischarge device I for defining a plurality of space resonant regionsMore particularly, in one form of my invention the space resonantregions may be defined in part by a plurality of substantiallyconcentric metallic or conductive cylinders 25, 26 and 21. Cylinders 25and 26 define the anode-grid space resonant region, and cylinders 26 and21 define the gridcathode space resonant region. Cylinder 26 may beconnected to disc I of the discharge device I through adapting means,such as a resilient annular member 28 of conductive character, to afforda suitable high frequency connection thereto, and a disc 8 may beconnected to cylinder 21 through an annular member 29 of metallicconstruction which may be secured rigidly to cylinder 21 by beingattached to a metallic ring 38 closely fitting to the inner surface ofcylinder 21. The combination of an electric discharge device havingtransverse disk-like terminals and concentric resonators, is describedand claimed in the copending Jensen and Keister application 448,206,filed June 24, 1942, and assigned to the assignee of this invention.

The discharge device I may be held rigidly in the position illustratedby using a onstruction which comprises a cylinder 3| which telescopescylinder 21 at one end thereof. Cylinder 3| is provided with a threadedcollar 32 to engage threads upon a portion of the outer surface ofcylinder 21. A metallic ring 33 is closely fitted to, or may be formedintegral with, cylinder 3| and constitute a means for supporting socket34 for discharge device I in position, and hence serves as a means forrigidly supporting the discharge device I in firm engagement withmembers 28 and 29.

In order to connect cylinder 25 to anode 2, and more particularly to thepart 24 thereof, I may employ a metallic adapter 35 which is, of course,conductively connected to cylinder 25. This adapter may be constructedof a solid metal such as brass or copper and be provided with a recessto receive the enlarged section 24 of the anode construction.

I provide means for tuning the space resonant regions. One of thesetuning means may be associatedwith the anode-grid region and maycomprise a piston 36 which i in engagement with and slideable along theouter surface of cylinder 25 and the inner surface of cylinder 26 andmay To apply unidirectional potential to the anode-.

grid circuit of the discharge device I, the anode 2 and moreparticularly the part 24 thereof may be connected to a source ofunidirectional potennected to adapter 35.

tial. by means of a cylindrical conductor lil which is positioned withincylinder 25 and which is con- Of course, the negative terminal of theunidirectional source is connected to contact pins II or I8 of thedischarge device through either terminal 40 or 4| of socket 34.

Energy may be derived from the anode-grid region of the system byemploying output electrode means which may comprise a loop 42constituting an extension of an inner conductor 43 of a concentrictransmission line 44. Of course, it is to be appreciated that otherforms of electrode means may be employed for extracting energy from thespace resonant system.

I provide within the cylinder 26 which defines the common boundarybetween the anode-grid and grid-cathode space resonant regions, anopening 45 having an appreciable axial or longitudinal dimension toafford sufiicient coupling between these regions throughout asubstantial range of the operating frequency of the system. Thisopening, which may have a configuration generally described as a narrowspiral or helical slot, is preferably positioned within the vicinity ofthe maximum of the standing potential wave,

in the anode-grid region.

I have found that in space resonant systems which may be operated ascoaxial wave propagating systems having Wave lengths which are oddmultiples of quarter wave lengths, such as threenuarters or fivequarters wave lengths, there are certain phase reversals which occurinside the lines or the region defined by the conductive members in sucha way that the cathode and anode potentials of the discharge device arebrought geometrically close to each other on opposite sides of themember which defines the common boundary between the two regions. Theexistence of this phenomenon is, of course, due to the self -shieldingcharacteristics of the respective coaxial lines. More particularly, itis due to the thin penetration depth of the current which permits theexistence of two individual and relativel independent currents onopposite sides of the same piece of metal defining the common boundarybetween the two regions. Consequently, the above described coupling slot45 is employed to supply the feed back connection required. The slot 45when placed at the proper position permits the flow of energy from oneside of cylinder 26 to the other side, thereby exciting the grid-cathoderegion at the proper'position to obtain the desired phase relationshipbetween the respective electrode voltages of the discharge device. Itwill be appreciated that there are a number of places or points at whichsuch a coupling slot may be located, the number of course depending uponthe electrical length of the space resonant regions under consideration.7

In accordance with another feature of my invention, cylinder 26 may beprovided with another opening 45, diametrically opposed .to opening 45.The two openings may operate in conjunction, or

discharge device I, the system will oscillate.

Energy may be derived from the anode-grid region through the concentric.transmission line 44 and supplied to an external or utilizationcircuit. The grid-cathode region is maintained in oscillation throughthe energy supplied thereto from the anode-grid cavity through openingor 85", or both, which constitute the coupling means. By virtue of thefact that the opening 45 or 45' has an appreciable axial length, itshould be appreciated that this feature permits substantial adjustmentof the operating frequency of the system without materially changing thecoupling between the anode-grid and the grid-cathode regions, therebydispensing with the necessity of adjustable coupling means or devices.By positioning openings 45 and 45 within the vicinity of the voltagemaximum of the standing electromagnetic wave within the anode-gridregion, suflicient coupling is provided throughout a range determined bythe efiective axial dimension of the openings.

The relation of the position of openings 45 and 45' with respect to thevoltage and current standing waves within the anode-grid regionmay bemor fully appreciated by referring to Fig. 3 which represents insimplified form the anodegrid region defined, by cylinders 26 and 21 andplunger 36 and which may be considered as constituting, for the purposesof analysis, a tuned three-quarter wave length coaxial line having aphysical length compensated for end-effects, and establishing standingvoltage and current waves A and B, respectively. Upon adjustment of theop erating frequency of the system, it will be appreciated that thevoltage maximum of the standing wave within the anode-grid region willchange in position. However, due to the helical shap of the openings 45and 45 the efiect of such a change in 6 defined bya pair 01'- outerconductive members and an intermediate conductive member, said'intermediate conductive member being provided with an opening located withinthe vicinity of the potential maximum of the standing electromagneticwave within one of said regions, said opening having both longitudinaland lateral progression along the surface of said intermediate member,

. and means for exciting said one of said regions.

position'of the voltage maximum does not change.

the coupling between the anode-grid and gridcathode regions andconsequently permits adjustment of the operating frequency withoutentailing a loss of output power.

While in the above description of my invention I have chosen to describeits operation with particular reference to an oscillator, it will beunderstood by those skilled in the art that itmay be applied to spaceresonant systemsgenerally where it is desired .to couple a pair orplurality of space resonant regions.

While I have shown and described my invention as applied to a particularsystem and as embodying various devices diagrammatically shown, it willbe obvious to those skilled'in the art that changes and modificationsmay be made without departing from myinvention, and I, therefore, aim inthe appended claims to cover all such changes and modifications as fallwithin the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A high frequency space resonant system comprising a plurality ofspace resonant regions 2. A high frequency space resonant systemcomprising a plurality of space resonant regionsdefined by a pluralityof cylindrical conductive members, the intermediate member defining thecommon boundary between the space resonant regions being provided with aslot located within the vicinity of the potential maximum of thestanding electromagnetic wave within one of said regions andconstituting coupling means between the regions, said slot having bothlongitudinal and tangential progression along the axis of saidintermediate member, and means for establishing an electromagnetic wavewithin one of said regions.

3. A high frequency space resonant system comprising a pair of spaceresonant regions defined by a plurality of concentric conductivecylinders, means for establishing an electromagnetic wave within one ofsaid regions, the intermediate cylinder defining the common boundarybetween said regions being provided with a pair of oppositely disposedslots located within the. vicinity of the potential maximum of thestanding electromagnetic wave within said one region said slotshavingboth longitudinal and tangential pro gression along the axis of saidintermediate cylinder.

4. A high frequency spac resonant system comprising a plurality of spaceresonant regions defined by a pair of outer conductive members and anintermediate conductive member, means for establishing anelectromagnetic Wave within one of said regions, and means forcontrolling the operating frequency of said space resonant system, saidintermediate conductive member being provided with a helical openinglocated within the vicinity of the potential maximum of the standingelectromagnetic wave within one of said regions thereby constituting acoupling path between said regions effective throughout a predeterminedrange of operating frequencies. v

5. A high frequency space resonant system comprising a plurality ofspace resonant regions defined'by a pair of outer conductive members andan intermediate conductive member, means for establishing anelectromagnetic wave within one of said regions, meansfor controllingthe operating frequency of said system, said intermediate member beingprovided with a helical opening located within the vicinity of thepotential maximum of the standing electromagnetic wave within said oneregion and having an appreciable axial dimension thereby constitutingcoupling means substantially independent of the operating frequency.

6. A high frequency space resonant system comprising an electricdischarge device including a plurality of enclosed electrodes includingan anode, a cathode and a grid, a plurality of conductive membersconnected to said electrodes to form anode-grid and grid-cathode spaceresonant regions, one of said members being provided with an openinghaving an appreciable axial length and tangential progression to form acommunicating path between said anode-grid and said grid-cathode regionslocated within the vlcinity of the maximum of the anode-grid regionstanding potential wave to afford substantial couplingbetween saidregions throughout an ape preciable range of operating frequencies ofsaid system. I I

7. --A high frequency space resonant system comprising an electricdischarge device including a plurality of enclosed electrodes includingan anode, a cathode and a grid, and a plurality of. substantiallyconcentric members connected respectively to said electrodesanddefining-anodegrid and grid-cathode space resonant regions, theintermediate member connected to said grid-being provided with anopeninglocated within the vicinity of the potential maximum of thestanding electromagnetic waveof said anode-grid region and havingappreciable axial length to afford substantial coupling between saidregions throughout the range of operating frequencies of said system.

. 8 A high frequency space resonant system comprising an electricdischarge device including a plurality of enclosed electrodes includingan anode, a cathode and a grid, and a plurality of substantiallyconcentric members connected respectively to said electrodes anddefining anodegrid and grid-cathode space resonant regions, th-intermediate member being provided with a helical opening constitutinga communicating path between said regions.

--9. A high frequency space resonant system comprising an electricdischarge device having aplurality of enclosed electrodes including ananode, a cathode and a grid and high frequency terminals therefor, threeconcentric conductive cylinders connected respectively to the terminalsfor said electrodes for defining anode-grid and grid-cathode spaceresonant regions, means for tuning at least one of said regions, theintermediate cylinder connected to said grid being provided with anopening constituting a communicating path between said regions andhaving-a substantial axial dimension to afford sufficient couplingthroughout a range of operating frequencies of said system.

I 10. A high frequency space resonant system comprisingan electricdischarge device including a plurality of enclosed electrodes includingan anode, a cathode and a grid, a plurality of substantially concentricconductive members con:

nected respectively to said electrodes and defining anode-grid andgrid-cathode space resonant regions, the intermediate member beingprovided with a helical opening constituting a communicating pathbetween regions, and means for tuning at least one of said regions. 11.A high frequency space resonant system comprising an electric dischargedevice including aplurality f enclosed electrodes including an anode, acathode and a grid, a plurality ofconductive members connected .to saidelectrodes to form anode-grid and grid-cathode space resonant regions,the member connected to said grid being provided with a narrow helicalslot located within the vicinity of the maximum of the anodegrid regionstanding potential wave, and means for tuning at least one of saidregions.

12. A high frequency space resonant system comprising an electricdischarge device includ-, ing a plurality of enclosed electrodesincluding an anode, acathode and a grid, a plurality of substantiallyconcentric conductive members con-, nected respectively to saidelectrodes anddeflning anode-grid and grid-cathode space resonantregions, the intermediate member connected to said grid being providedwith a pair of opposed openings located within the vicinity of thepoten-. tial maximum of .the standing electromagnetic wave of saidanode-grid region and constitute ing coupling means between theanode-grid and the grid-cathode space resonant regions.

13. A high frequency space resonant system comprising an electricdischarge devic includ ing; a. plurality of enclosed electrodesincluding an anode, a cathode and a grid, a plurality of cylindricalconductive members connected to said electrodes to form anode-grid andgrid-cathode space resonant regions, and a pair of diametrically opposedcoupling paths in the cylinder defining the common boundary between theanode: grid and the grid-cathode space resonant re gions, said cylinderbeing provided with helical slots to form said paths.

14. A high frequency space resonant system comprising an electricdischarge device including a plurality of enclosed electrodes includingan anode, a cathode and a grid, a plurality of substantially concentricconductive cylinders connected respectively to said electrodes .anddefining anode-grid and grid-cathode space resonant regions, theintermediate cylinder connected to said grid being provided with a pairof diametrically opposed and longitudinally and tangential,- lyprogressive slots located within the vicinity of the potential maximumof the standing electromagnetic wave of said anode-grid region therebyconstituting coupling means between the anode-grid and the grid-cathodespace resonant regions. r

15. A high frequency space resonant system comprising an electricdischarge device includ ing a plurality of enclosed electrodes includingan anode, a cathode and agrid, a plurality of sub stantially concentricconductive members con nected respectively to said electrodes and defineing anode-grid and grid-cathode space resonant regions, the intermediatemember connected to said grid being provided with a. pair of. slotshaving reverse curvatures relative to the'longi-v tudinal axis of saidregions thereby'constituting coupling means between the anode-grid andthe grid-cathode space resonant regions.

ELMER D.McARTI-1UR. I

' REFERENCES CITED The following references are of record in the file ofthis patent:

Trevor Apr. 29, 1941

